Superheater boiler



Mar. 27, 1923.

A. COTTON SUPERHEATER BOILER Filed Apll. 29, 1920 Patented Mar. 27,1923.

rUNITED STATES 1,450,021 PATENT OFFICE.

ALFRED COTTON, OF ST. LOUIS, MISSOURI, ASSIGNOR TO HEINE BOILER COMPANY,F

ST. LOUIS, MISSOURI, A CORPORATION 0F MISSOURI.

" SUPERHEATER BOILER.

" T 0 all whom t may coowem: p

Be it known that 1, ALFRED Co'rroN, a citizen of the United States,residing at St. Louis, Missouri, ave invented a certain new and usefulImprovement in Superheater Boilers, of which the following is a full,clear, and exact description, such as will enable others skilled in theart to which it appertains to make and use the same. This inventionrelates lte water tube boilers ofthe cross drum, upright tube type.

One object of my present invention is to provide a superheater boiler ofthe general type referred to which is of such design that agreaterdegree of superheat can be obtained than is possible with superheaterboilers of the kind now 'in use,.thereby increasing the eiiciency of theboiler when it is, equipped with a superheater of conventionallsiZe,-'or permitting a small superheater to be used without reducingthe eiiiciency of the boiler.

Another object is to provide a superheater boiler which is solconstructed that the amount of superheat can be accurately regulated.Other objects and desirable features of my invention will be hereinafterpointed out.

To this end I have devised a boiler which comprises a number of crossdrums and a number 'of banks of upright water tubes connected with saidcross drums, a super.

heater arranged preferably in the space between the first and secondtube banks, and a y shield or partition arranged near the front side ofthe first tube bank in such a manner that the long flame or hydrocarbongases from the front of the fire will travel the full height of thecombustion chamber before crossing over the first tube bank and theshort iame gases from the back of the fire will escape from thecombustion cham` ber under the lower edge of said shield and then divideor split up into two streams, oneof said streams entering thesuperheater chamber and the other stream flowy ing upwardly among thetubes of the first bank.

Tghe Figure of the drawing is a vertical sectional View of a superheaterboiler constructed in accordance with my invention.

Referringvto the drawings, 1 designates the first bank of water tubes, 2the second or middle bank,3 the third or rear bank, 4

the mud drum to which the feed water` is supplied, 5,6 and 7 the front,middle and i rear steam-and-water drums that communi,

cate with the upper ends of the tubes of the banks 1, 2 and 3,respectively, 8 the water circulators and 9 thev steam circulators thatconnect the frontj drum 5 with the middle drum 6, and 10 and 11 thewater respectively, that and steam circulators, connect the middle drum6 with thaerear drum 7 the steam outlet 12 preferably leading from therear drum 7. A shield or partition A islarranged at the front side ofthe first tube bank l, so as' to cause the long flame gases, vindicatedby the arrows w, rising from the front of the fire, to travel slowlyupwardly through the combustion chamber B and then flow rearwardly overthe upper edge of said shield A across the tubes of the first bank 1,and the short fiame gases, indicated by the arrows marked y,.rising fromthe back of the fire, to escape from the combustion chamber under thelower edgeof the partition A and follow a different path than said longflame gases. The shield or partition A produces the same results as theshield or partition of the boiler described .in my pending applicationfor patent Serial No. 373,250, filed April 12, 1920, and can beconstructed in various ways without departing from the spirit of myinvention.

A superheater C is arranged in a chamber between the first and secondtube banks in such a manner that part of the short flame gases from theback of the fire will enter the lower end of said superheater chamber,flow upwardlyLthrough same over the superheater C and th escape from theupper end of said chamber, as indicated by y the arrows in the drawing.Said superheater chamber is formed by a baiie D arranged at the rearside of the first tube bank 1 and a baffle E arranged at the front sideof the second tube bank 2, the baffleI D having its upper and loweredges spaced. away from the front steam-and-water drum 5 and from themud drum 4, so as to form passageways throu h which the gases cantravel, and the baiiiegl` extending upwardly from the mud drum L i andterminating at a point below the middle steam-and-water drum 6. Thebafiie D is provided with a rearwardly-projecting shelf 13 that formsthe top side orl wall of the superheater chamber, and a controlling Lealvalve or damper 14 is arranged adjacent the the mud drum 4 so as tocause the gases tov flow downwardly among the tubes of the second bankand then upwardly among the tubes of the third bank to a dischargeopening 16 at the upper end of the boiler,

Then the boiler is in operation the long flame gases from the front ofthe fire travel slowly upwardly through the combustion chamber and thenflow rearwardly over the upper edge of the shield A across the tubes ofthe front bank l. T he short flame gases y from the back of the fireescape from the combustion chamber under the lower edge of the shield Aand enter the front tube bank 1 at lthe lower end of said bank.

These short fiame gases are again split up into two streams by thebaffle D that forms the front wall of the superheater chamber, part ofsaid gases flowing upwardly among the tubes of the first bank l and theremainder passing into the superheater chamber` under the bottom edge ofthe baffle D. Due to the fact that the short flame gases from the backof the fire require only a short time and small space to completecombustion, combustion of the gases used -to heat the superheater iscomplete before said gases enter the superheater chamber. Moreover, asthe gaseswhich pass through the superheater chamber have made only asmall contact with the. heating surface of the boiler since they passstraight across the lower end portion of the first tube bank l, saidgases are much hotter than gases which have made a full pass over thefirst 'tube bank of the boiler before impinging upon the superheater.Consequently, the superheater of my boiler will give a much higherdegree of superheat than the superheater of a cross drum, upright tubesuperheater boiler of the kind now in general use.v This isadvantageous, in that the efficiency of the boiler is materiallyincreased when it is equipped with a superheater of conventional size,and it makes it possible to materially reduce the size of thesuperheater without decreasing the efficiency of the boiler. In thesuperheater boilers of the kind now in general use the superheater isgenerally arranged in parallel relation with one of the tube banks, thusmaking it difficult to control the amount of superheat. In my improvedboiler the` amount of gases passing over the superheater can beaccurately controlled,and consequently, the amount of superheat may beregulated either automatically or by hand.

In order to attain sufiicient superheat with controlled gas flow, itmeans that the desired amount of superheat must be possible ofattainment with less than the maximum gas flow. If, with a givensuperheater (such as is usually attached to a Stirling boiler) all thegases are necessary to give sufficient superheat, then with the samesize of superheater with a diminished gas flow or controlled gas flow,the gases must be hotter than usual. vIf the superheater is heatedmerely by a portion of the mixed hot gases from the combustion chamber,or by gases that have passed over only a small amount of heating surfaceof the boiler, two difi'lculties, due to incomplete combustion, areexperienced. One is, that secondary combustion is liable to take placein the superheater chamber, thus varying the amount of superheatattained and making it almost impossible to control the superheat. rllheother is that soot is deposited on the superheater elements, reducingtheir efficiency and mak-4 ing accurate control of the temperature ofthe superheated steam more difficult.

By constructing the boiler so that the shortest of the short flame gasesonly enter the superheater chamber, combustion is quite complete beforethe gases enter the superheater chamber, and consequently, delayedcombustion inside of the superheater chamber is avoided. As the gaseswhich are used to heat the superheaterl are derived from that part ofthe fire where there is little or no hydrocarbon, deposits of soot onthe superheater elements is avoided.

I am aware of the fact that it is old to arrange a superheater betweenthe front and middle banks of tubes of a Stirling boiler, but myimproved boiler is distinguished from the usual Stirling superheaterboiler,

in that it is so constructed that the super-- heater is heated by acontrolled lflow of gases taken from the extreme rear end of the fire.

Having thus described my invention, what I claim as new and desire tosecure by Let- Aters Patent is: l

l.' A boiler of the semi-vertical tube vtype provided with a front bankof water tubes, a superheater arranged behind said front bank, means forcausinofthe long fiame gases fromthe front of the'ffre to travelupwardly through the combustion chamber before coming in cont-act withthe main body of tubes of the front bank, and means for causing theshort flame gases from the back ofthe fire` to separate into twostreams, one of which streams fiows upwardlyl over the superheater andthe other upwardly among the tubes of the front bank.

2. A boilerl of the semi-vertical water tube type haying threetransverse steam-and-water tubes, means for causing the gases from thefront of the fire to travel upwardly through the combustion chamberbefore coming in contact with the main body of tubes of the first bank,and means for causing the gases from the back ofthe fire' to separateinto two streams, one of which streams flows upwardly among the mainbody of tubes of .the first bank and the other upwardly over the ysuperheater.

Aandlthen rearwardly across the upperv por# tion of the rst tube bank,and means for causing theshort flame gases from the rear of the fire toseparate into two streams, one

l of which streams enters the superheater chamber, th'e other fiowingupwardly among the tubes of the first bank.

4. A water tube boiler provided with a plurality of banks of uprighttubes, a superheater chamber arranged between the first, and second tubebanks and provided at its lower end with an inlet and at its upper endwith an outlet, a damper for controlling the outlet of said chamber, anda partition arranged at the front side of the first tube bank in such amanner that the long fiame gases from the front of the fire will flowupwardly through the combustion chamber and then rearwardly across theupper portion of the first tube bank and the short flame gases from theback of the fire will enter the lower end vof the first tube` bank, theinlet of the d superheater chamber beingr located adjacent the lowerend'of same so that a portion of the short fiame gases will pass intothe superheater chamber through said inlet.

5; A water tube boiler of the upright tube type provided with threebanks of upright water tubes, a mud drum communicating with the lowerends of said tube banks, cross drums communicating with the upper endsof said tube banks, a partition arranged at the front side of the firsttube bank with its upper and loweredges spaced away from the front drumand mud drum, respectively, a baffle arranged at the rear side of saidfirst tube bank with its upper and lower edges spaced away from thefront drum and mud drum, respectively, for the purpose described, asuperheater arranged at the rear side of said bafiie, and bafflesarranged at the front and rear sides of the second tube bank in such amanner that the gases will flow downwardly among the tubes of the secondbank and then upwardly among the tubes of i the third bank. A

ALFRED ooT'roN.

